i810 vs. intel: frequency differences?

Tom London selinux at gmail.com
Fri Apr 13 17:37:19 UTC 2007


On 4/13/07, Adam Jackson <ajackson at redhat.com> wrote:
> On Fri, 2007-04-13 at 09:39 -0700, Tom London wrote:
> > Running xorg-x11-drv-i810-1.6.5-19.fc7, I've noticed that seem to
> > drive different monitor frequencies for the same
> > monitor/settings/xorg.conf.
> >
> > Running on two different LCD monitors, if my xorg.conf says 'i810', I
> > consistently get Horiz rate of 79.8kHz and Vert rate of 74.6Hz.
> >
> > If I only change i810->intel and restart X, I consistently get Horiz
> > rate of 83.0kHz and Vert rate of 77.8Hz (the last is above supported
> > rate (~75Hz) for both monitors).
>
> The X log, at least for the intel run, should show the exact timings
> being sent to the monitor, as well as what the monitor reports for
> capabilities.  That said, there could easily be bugs in the intel
> driver.
>
> > I've also noticed inconsistencies between the rates reported by my
> > monitors and that reported by xrandr when I run with 'intel': xrandr
> > reports Horiz is 80kHz (vs. monitor reporting 83kHz) and Vert is 75Hz
> > (vs. monitor reporting 77.8Hz).
>
> Rounding error.  Monitors are not particularly smart.
>
> - ajax
>
Would normally agree about 'rounding error', but setting the driver to
'intel' puts 2 monitors 'out of range' for Horiz.  Also, the monitors
have no problem reporting 74.6 for 'i810' vs. 77.8 for 'intel'.  There
must be a difference in the actual signal.  No?

What exactly from Xorg.0.log would be useful for me to provide?

tom
-- 
Tom London




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